Compasses or dividers are instruments for the drawing of cirles or curves, for the measuring of dimensions and the transferring of distances. The ordinary compasses consist of two hingedly connected legs, one of which is equipped with a steel point, while the other, in most cases provided with an additional joint, carries a replaceable drawing insert, such as a cartridge, a drawing pen or the like, which may frequently also be replaced with a second steel point. When working with compasses or dividers of this type, there often arises the problem of circles having certain radii having to be drawn where the adherence to the exact radius is of prime importance. In order to adhere to a pertinent accuracy, the known compasses have to be lined up against a measuring ruler provided with appropriate lengthwise graduations and the relevant graduation has to be measured in this case.
After that the compasses, provided they do not possess a locking device, have to be correspondingly carefully placed on the drawing plate or the like in order to there draw or scribe the relevant radius. However, when this is done, the pertinent elasticities of the legs which, by way of example, when the leg is pressed on, may lead to an inadvertent enlargement of the radius. Moreover, the measuring of predetermined radii dimensions constitutes an additional strain when drawing.
For this reason compasses have already been proposed in which the first leg is provided with a measuring and mounting facility which, at one of its ends, is linked to the first leg, and, at its other end, is provided with a scribing device, the measuring and mounting facility having an aperture through which a measuring ruler on which lengthwise graduations have been applied can be passed which, with one of its ends, is detachably secured to the carrying element of the second leg and which projects with its other free end which can be passed through the aperture (FR-PS No. 1.441.541).
Compasses are also already known on the one leg of which the one end of a measuring ruler is arranged which, with its other free end, can be passed through an aperture in the second leg (DE-PS No. 60665).
In another known embodiment of a pair of compasses provision is made for a pair of measuring compasses being pivotably arranged on one of the legs, while on the other leg a facility for reading the lengthwise graduations of the measuring ruler is disposed. However, in this case no exact assignment between the scribing spike of the leg and the lengthwise graduations of the measuring ruler is provided (DE-OS No. 34 42 675).
It is therefore the object of the present invention to further refine a pair of compasses in such a way that the measuring of the dimensions to be drawn or scribed can be dispensed with and that the dimensions to be set can be read off the compasses direct while avoiding elasticity influences in the compasses.
This technical problem is solved by the features characterized in claim 1.